[PATCH] xhci: Introduce max wait timeout in xhci_handshake()

[PATCH] xhci: Introduce max wait timeout in xhci_handshake()

[Chen Yu]

The time to finish a xhci_handshake() is platform specific
and sometimes during suspend resume test the followng
errors were encountered:
[53455.418330] ACPI: Waking up from system sleep state S4
[66838.490856] xhci_hcd 0000:00:14.0: xHCI dying, ignoring interrupt.
               Shouldn't IRQs be disabled?
After changing the poll time granularity from 1 usec to 20 usec in
xhci_handshake() this issue was not reproduced. While tuning on the
poll time granularity might be painful on different platforms, it is
applicable to introduce a module parameter to allow the xhci driver to wait
for at max 16 ms.

Reported-by: "Muchowski, MaciejX" <maciejx.muchowski@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
---
 drivers/usb/host/xhci.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index d4a8d0efbbc4..b8be9f3cc987 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -38,6 +38,10 @@ static unsigned long long quirks;
 module_param(quirks, ullong, S_IRUGO);
 MODULE_PARM_DESC(quirks, "Bit flags for quirks to be enabled as default");
 
+static int wait_handshake;
+module_param(wait_handshake, int, 0644);
+MODULE_PARM_DESC(wait_handshake, "Force wait for completion of handshake");
+
 static bool td_on_ring(struct xhci_td *td, struct xhci_ring *ring)
 {
 	struct xhci_segment *seg = ring->first_seg;
@@ -74,7 +78,7 @@ int xhci_handshake(void __iomem *ptr, u32 mask, u32 done, int usec)
 	ret = readl_poll_timeout_atomic(ptr, result,
 					(result & mask) == done ||
 					result == U32_MAX,
-					1, usec);
+					1, wait_handshake ? XHCI_MAX_HALT_USEC : usec);
 	if (result == U32_MAX)		/* card removed */
 		return -ENODEV;
 
-- 
2.17.1

Re: [PATCH] xhci: Introduce max wait timeout in xhci_handshake()

[Greg KH]

On Tue, Dec 15, 2020 at 09:22:40PM +0800, Chen Yu wrote:
> The time to finish a xhci_handshake() is platform specific
> and sometimes during suspend resume test the followng
> errors were encountered:
> [53455.418330] ACPI: Waking up from system sleep state S4
> [66838.490856] xhci_hcd 0000:00:14.0: xHCI dying, ignoring interrupt.
>                Shouldn't IRQs be disabled?
> After changing the poll time granularity from 1 usec to 20 usec in
> xhci_handshake() this issue was not reproduced. While tuning on the
> poll time granularity might be painful on different platforms, it is
> applicable to introduce a module parameter to allow the xhci driver to wait
> for at max 16 ms.
> 
> Reported-by: "Muchowski, MaciejX" <maciejx.muchowski@intel.com>

I doubt the "X" is part of this person's name, please just spell it out
without the "," please.

> Signed-off-by: Chen Yu <yu.c.chen@intel.com>
> ---
>  drivers/usb/host/xhci.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index d4a8d0efbbc4..b8be9f3cc987 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -38,6 +38,10 @@ static unsigned long long quirks;
>  module_param(quirks, ullong, S_IRUGO);
>  MODULE_PARM_DESC(quirks, "Bit flags for quirks to be enabled as default");
>  
> +static int wait_handshake;
> +module_param(wait_handshake, int, 0644);
> +MODULE_PARM_DESC(wait_handshake, "Force wait for completion of handshake");

This is not the 1990's, we are not adding new module parameters that no
one will know how to change.

Make this dynamic, and per-device, and work properly instead.  This can
not handle multiple controllers in the system at all :(

thanks,

greg k-h

Re: [PATCH] xhci: Introduce max wait timeout in xhci_handshake()

[Chen Yu]

Hi Greg,
thanks for taking a look at this.
On Tue, Dec 15, 2020 at 02:39:14PM +0100, Greg KH wrote:
> On Tue, Dec 15, 2020 at 09:22:40PM +0800, Chen Yu wrote:
> > The time to finish a xhci_handshake() is platform specific
> > and sometimes during suspend resume test the followng
> > errors were encountered:
> > [53455.418330] ACPI: Waking up from system sleep state S4
> > [66838.490856] xhci_hcd 0000:00:14.0: xHCI dying, ignoring interrupt.
> >                Shouldn't IRQs be disabled?
> > After changing the poll time granularity from 1 usec to 20 usec in
> > xhci_handshake() this issue was not reproduced. While tuning on the
> > poll time granularity might be painful on different platforms, it is
> > applicable to introduce a module parameter to allow the xhci driver to wait
> > for at max 16 ms.
> > 
> > Reported-by: "Muchowski, MaciejX" <maciejx.muchowski@intel.com>
> 
> I doubt the "X" is part of this person's name, please just spell it out
> without the "," please.
> 
Okay, will do.
> > Signed-off-by: Chen Yu <yu.c.chen@intel.com>
> > ---
> >  drivers/usb/host/xhci.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> > index d4a8d0efbbc4..b8be9f3cc987 100644
> > --- a/drivers/usb/host/xhci.c
> > +++ b/drivers/usb/host/xhci.c
> > @@ -38,6 +38,10 @@ static unsigned long long quirks;
> >  module_param(quirks, ullong, S_IRUGO);
> >  MODULE_PARM_DESC(quirks, "Bit flags for quirks to be enabled as default");
> >  
> > +static int wait_handshake;
> > +module_param(wait_handshake, int, 0644);
> > +MODULE_PARM_DESC(wait_handshake, "Force wait for completion of handshake");
> 
> This is not the 1990's, we are not adding new module parameters that no
> one will know how to change.
>
Okay.
> Make this dynamic, and per-device, and work properly instead.  This can
> not handle multiple controllers in the system at all :(
>
Okay. After checking the error log, enlarging the timeout might not be enough
and I'll dig into it a little deeper and send feedback.

thanks,
Chenyu
> thanks,
> 
> greg k-h